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Btrfs: Block sized tree extents and extent deletion

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2007-02-23 08:38:36 -05:00 committed by David Woodhouse
parent 5c680ed620
commit 9a8dd1502d
5 changed files with 253 additions and 136 deletions
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247
fs/btrfs/ctree.c
View file

@ -8,9 +8,12 @@
#define SEARCH_READ 0 #define SEARCH_READ 0
#define SEARCH_WRITE 1 #define SEARCH_WRITE 1
static int refill_alloc_extent(struct ctree_root *root); #define CTREE_EXTENT_PENDING 0
int split_node(struct ctree_root *root, struct ctree_path *path, int level); int split_node(struct ctree_root *root, struct ctree_path *path, int level);
int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size); int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size);
struct tree_buffer *alloc_free_block(struct ctree_root *root);
int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks);
static inline void init_path(struct ctree_path *p) static inline void init_path(struct ctree_path *p)
{ {
@ -682,8 +685,6 @@ int insert_item(struct ctree_root *root, struct key *key,
unsigned int data_end; unsigned int data_end;
struct ctree_path path; struct ctree_path path;
refill_alloc_extent(root);
/* create a root if there isn't one */ /* create a root if there isn't one */
if (!root->node) if (!root->node)
BUG(); BUG();
@ -756,6 +757,7 @@ int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
struct tree_buffer *t; struct tree_buffer *t;
struct node *node; struct node *node;
int nritems; int nritems;
u64 blocknr;
while(1) { while(1) {
t = path->nodes[level]; t = path->nodes[level];
@ -774,6 +776,7 @@ int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
} }
node->header.nritems--; node->header.nritems--;
write_tree_block(root, t); write_tree_block(root, t);
blocknr = t->blocknr;
if (node->header.nritems != 0) { if (node->header.nritems != 0) {
int tslot; int tslot;
if (slot == 0) if (slot == 0)
@ -799,6 +802,7 @@ int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
break; break;
} }
level++; level++;
free_extent(root, blocknr, 1);
if (!path->nodes[level]) if (!path->nodes[level])
BUG(); BUG();
} }
@ -841,8 +845,10 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
if (leaf_buf == root->node) { if (leaf_buf == root->node) {
leaf->header.flags = node_level(0); leaf->header.flags = node_level(0);
write_tree_block(root, leaf_buf); write_tree_block(root, leaf_buf);
} else } else {
del_ptr(root, path, 1); del_ptr(root, path, 1);
free_extent(root, leaf_buf->blocknr, 1);
}
} else { } else {
if (slot == 0) if (slot == 0)
fixup_low_keys(root, path, &leaf->items[0].key, 1); fixup_low_keys(root, path, &leaf->items[0].key, 1);
@ -867,6 +873,72 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
return 0; return 0;
} }
static int del_pending_extents(struct ctree_root *extent_root)
{
int ret;
struct key key;
struct tree_buffer *gang[4];
int i;
struct ctree_path path;
while(1) {
ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
(void **)gang, 0, ARRAY_SIZE(gang),
CTREE_EXTENT_PENDING);
if (!ret)
break;
for (i = 0; i < ret; i++) {
key.objectid = gang[i]->blocknr;
key.flags = 0;
key.offset = 1;
init_path(&path);
ret = search_slot(extent_root, &key, &path, 0);
if (ret) {
BUG();
// FIXME undo it and return sane
return ret;
}
ret = del_item(extent_root, &path);
if (ret) {
BUG();
return ret;
}
release_path(extent_root, &path);
radix_tree_tag_clear(&extent_root->cache_radix, gang[i]->blocknr,
CTREE_EXTENT_PENDING);
tree_block_release(extent_root, gang[i]);
}
}
return 0;
}
int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
{
struct ctree_path path;
struct key key;
struct ctree_root *extent_root = root->extent_root;
struct tree_buffer *t;
int pending_ret;
int ret;
key.objectid = blocknr;
key.flags = 0;
key.offset = num_blocks;
if (root == extent_root) {
t = read_tree_block(root, key.objectid);
radix_tree_tag_set(&root->cache_radix, key.objectid, CTREE_EXTENT_PENDING);
return 0;
}
init_path(&path);
ret = search_slot(extent_root, &key, &path, 0);
if (ret)
BUG();
ret = del_item(extent_root, &path);
release_path(extent_root, &path);
pending_ret = del_pending_extents(root->extent_root);
return ret ? ret : pending_ret;
}
int next_leaf(struct ctree_root *root, struct ctree_path *path) int next_leaf(struct ctree_root *root, struct ctree_path *path)
{ {
int slot; int slot;
@ -904,8 +976,8 @@ int next_leaf(struct ctree_root *root, struct ctree_path *path)
return 0; return 0;
} }
int alloc_extent(struct ctree_root *orig_root, u64 num_blocks, u64 search_start, int find_free_extent(struct ctree_root *orig_root, u64 num_blocks, u64 search_start,
u64 search_end, u64 owner, struct key *ins) u64 search_end, struct key *ins)
{ {
struct ctree_path path; struct ctree_path path;
struct key *key; struct key *key;
@ -915,15 +987,13 @@ int alloc_extent(struct ctree_root *orig_root, u64 num_blocks, u64 search_start,
u64 last_block; u64 last_block;
int start_found = 0; int start_found = 0;
struct leaf *l; struct leaf *l;
struct extent_item extent_item;
struct ctree_root * root = orig_root->extent_root; struct ctree_root * root = orig_root->extent_root;
init_path(&path); init_path(&path);
ins->objectid = search_start; ins->objectid = search_start;
ins->offset = 0; ins->offset = 0;
ins->flags = 0; ins->flags = 0;
ret = search_slot(root, ins, &path, 0);
ret = search_slot(root, ins, &path, sizeof(struct extent_item));
while (1) { while (1) {
l = &path.nodes[0]->leaf; l = &path.nodes[0]->leaf;
slot = path.slots[0]; slot = path.slots[0];
@ -938,6 +1008,7 @@ int alloc_extent(struct ctree_root *orig_root, u64 num_blocks, u64 search_start,
ins->objectid = search_start; ins->objectid = search_start;
ins->offset = num_blocks; ins->offset = num_blocks;
hole_size = search_end - search_start; hole_size = search_end - search_start;
start_found = 1;
goto insert; goto insert;
} }
ins->objectid = last_block; ins->objectid = last_block;
@ -956,51 +1027,119 @@ int alloc_extent(struct ctree_root *orig_root, u64 num_blocks, u64 search_start,
} else } else
start_found = 1; start_found = 1;
last_block = key->objectid + key->offset; last_block = key->objectid + key->offset;
insert_failed:
path.slots[0]++; path.slots[0]++;
} }
// FIXME -ENOSPC // FIXME -ENOSPC
insert: insert:
release_path(root, &path); if (orig_root->extent_root == orig_root) {
extent_item.refs = 1; BUG_ON(num_blocks != 1);
extent_item.owner = owner; if ((root->current_insert.objectid <= ins->objectid &&
if (root == orig_root && root->reserve_extent->num_blocks == 0) { root->current_insert.objectid + root->current_insert.offset >
root->reserve_extent->blocknr = ins->objectid; ins->objectid) ||
root->reserve_extent->num_blocks = ins->offset; (root->current_insert.objectid > ins->objectid &&
root->reserve_extent->num_used = 0; root->current_insert.objectid <= ins->objectid + ins->offset) ||
radix_tree_tag_get(&root->cache_radix, ins->objectid,
CTREE_EXTENT_PENDING)) {
last_block = ins->objectid + 1;
search_start = last_block;
goto insert_failed;
}
} }
ret = insert_item(root->extent_root, ins, &extent_item, sizeof(extent_item)); release_path(root, &path);
return ret; if (ins->offset != 1)
BUG();
return 0;
} }
static int refill_alloc_extent(struct ctree_root *root) static int insert_pending_extents(struct ctree_root *extent_root)
{ {
struct alloc_extent *ae = root->alloc_extent;
struct key key;
int ret; int ret;
int min_blocks = MAX_LEVEL * 2; struct key key;
struct extent_item item;
struct tree_buffer *gang[4];
int i;
if (ae->num_blocks > ae->num_used && ae->num_blocks - ae->num_used > // FIXME -ENOSPC
min_blocks) item.refs = 1;
return 0; item.owner = extent_root->node->node.header.parentid;
ae = root->reserve_extent; while(1) {
if (ae->num_blocks > ae->num_used) { ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
if (root->alloc_extent->num_blocks == 0) { (void **)gang, 0, ARRAY_SIZE(gang),
/* we should swap reserve/alloc_extent when alloc CTREE_EXTENT_PENDING);
* fills up if (!ret)
*/ break;
BUG(); for (i = 0; i < ret; i++) {
key.objectid = gang[i]->blocknr;
key.flags = 0;
key.offset = 1;
ret = insert_item(extent_root, &key, &item, sizeof(item));
if (ret) {
BUG();
// FIXME undo it and return sane
return ret;
}
radix_tree_tag_clear(&extent_root->cache_radix, gang[i]->blocknr,
CTREE_EXTENT_PENDING);
tree_block_release(extent_root, gang[i]);
} }
if (ae->num_blocks - ae->num_used < min_blocks) }
BUG(); return 0;
}
int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
u64 search_end, u64 owner, struct key *ins, struct tree_buffer **buf)
{
int ret;
int pending_ret;
struct extent_item extent_item;
extent_item.refs = 1;
extent_item.owner = owner;
ret = find_free_extent(root, num_blocks, search_start, search_end, ins);
if (ret)
return ret;
if (root != root->extent_root) {
memcpy(&root->extent_root->current_insert, ins, sizeof(*ins));
ret = insert_item(root->extent_root, ins, &extent_item, sizeof(extent_item));
memset(&root->extent_root->current_insert, 0, sizeof(struct key));
pending_ret = insert_pending_extents(root->extent_root);
if (ret)
return ret;
if (pending_ret)
return pending_ret;
*buf = find_tree_block(root, ins->objectid);
return 0; return 0;
} }
ret = alloc_extent(root, /* we're allocating an extent for the extent tree, don't recurse */
min_blocks * 2, 0, (unsigned long)-1, BUG_ON(ins->offset != 1);
root->node->node.header.parentid, &key); *buf = find_tree_block(root, ins->objectid);
ae->blocknr = key.objectid; BUG_ON(!*buf);
ae->num_blocks = key.offset; radix_tree_tag_set(&root->cache_radix, ins->objectid, CTREE_EXTENT_PENDING);
ae->num_used = 0; (*buf)->count++;
return ret; return 0;
}
struct tree_buffer *alloc_free_block(struct ctree_root *root)
{
struct key ins;
int ret;
struct tree_buffer *buf = NULL;
ret = alloc_extent(root, 1, 0, (unsigned long)-1, root->node->node.header.parentid,
&ins, &buf);
if (ret) {
BUG();
return NULL;
}
if (root != root->extent_root)
BUG_ON(radix_tree_tag_get(&root->extent_root->cache_radix, buf->blocknr,
CTREE_EXTENT_PENDING));
return buf;
} }
void print_leaf(struct leaf *l) void print_leaf(struct leaf *l)
@ -1096,6 +1235,7 @@ int main() {
print_tree(root, root->node); print_tree(root, root->node);
printf("map tree\n"); printf("map tree\n");
print_tree(root->extent_root, root->extent_root->node); print_tree(root->extent_root, root->extent_root->node);
fflush(stdout);
srand(55); srand(55);
for (i = 0; i < run_size; i++) { for (i = 0; i < run_size; i++) {
@ -1111,12 +1251,6 @@ int main() {
if (!ret) if (!ret)
tree_size++; tree_size++;
} }
printf("root used: %lu\n", root->alloc_extent->num_used);
printf("root tree\n");
// print_tree(root, root->node);
printf("map tree\n");
printf("map used: %lu\n", root->extent_root->alloc_extent->num_used);
// print_tree(root->extent_root, root->extent_root->node);
write_ctree_super(root, &super); write_ctree_super(root, &super);
close_ctree(root); close_ctree(root);
@ -1167,12 +1301,27 @@ int main() {
ret = insert_item(root, &ins, buf, strlen(buf)); ret = insert_item(root, &ins, buf, strlen(buf));
if (!ret) if (!ret)
tree_size++; tree_size++;
if (i >= 5) {
struct key ugh;
ugh.objectid = 5;
ugh.flags = 0;
ugh.offset = 0;
init_path(&path);
ret = search_slot(root, &ugh, &path, 0);
if (ret) {
print_tree(root, root->node);
printf("unable to find 5 %d\n", num);
exit(1);
}
release_path(root, &path);
}
} }
write_ctree_super(root, &super); write_ctree_super(root, &super);
close_ctree(root); close_ctree(root);
root = open_ctree("dbfile", &super); root = open_ctree("dbfile", &super);
printf("starting search2\n");
srand(128); srand(128);
printf("starting search2\n");
for (i = 0; i < run_size; i++) { for (i = 0; i < run_size; i++) {
num = next_key(i, max_key); num = next_key(i, max_key);
ins.objectid = num; ins.objectid = num;
@ -1219,5 +1368,7 @@ int main() {
write_ctree_super(root, &super); write_ctree_super(root, &super);
close_ctree(root); close_ctree(root);
printf("tree size is now %d\n", tree_size); printf("tree size is now %d\n", tree_size);
printf("map tree\n");
print_tree(root->extent_root, root->extent_root->node);
return 0; return 0;
} }

13
fs/btrfs/ctree.h
View file

@ -28,21 +28,12 @@ struct header {
struct tree_buffer; struct tree_buffer;
struct alloc_extent {
u64 blocknr;
u64 num_blocks;
u64 num_used;
} __attribute__ ((__packed__));
struct ctree_root { struct ctree_root {
struct tree_buffer *node; struct tree_buffer *node;
struct ctree_root *extent_root; struct ctree_root *extent_root;
struct alloc_extent *alloc_extent; struct key current_insert;
struct alloc_extent *reserve_extent;
int fp; int fp;
struct radix_tree_root cache_radix; struct radix_tree_root cache_radix;
struct alloc_extent ai1;
struct alloc_extent ai2;
}; };
struct ctree_root_info { struct ctree_root_info {
@ -52,8 +43,6 @@ struct ctree_root_info {
u64 tree_root; /* the tree root */ u64 tree_root; /* the tree root */
u32 csum; u32 csum;
u32 ham; u32 ham;
struct alloc_extent alloc_extent;
struct alloc_extent reserve_extent;
u64 snapuuid[2]; /* root specific uuid */ u64 snapuuid[2]; /* root specific uuid */
} __attribute__ ((__packed__)); } __attribute__ ((__packed__));

90
fs/btrfs/disk-io.c
View file

@ -12,33 +12,13 @@
static int allocated_blocks = 0; static int allocated_blocks = 0;
static int get_free_block(struct ctree_root *root, u64 *block) static int check_tree_block(struct ctree_root *root, struct tree_buffer *buf)
{ {
struct stat st; if (buf->blocknr != buf->node.header.blocknr)
int ret = 0; BUG();
if (root->node && buf->node.header.parentid != root->node->node.header.parentid)
if (root->alloc_extent->num_used >= root->alloc_extent->num_blocks) BUG();
return -1; return 0;
*block = root->alloc_extent->blocknr + root->alloc_extent->num_used;
root->alloc_extent->num_used += 1;
if (root->alloc_extent->num_used >= root->alloc_extent->num_blocks) {
struct alloc_extent *ae = root->alloc_extent;
root->alloc_extent = root->reserve_extent;
root->reserve_extent = ae;
ae->num_blocks = 0;
}
st.st_size = 0;
ret = fstat(root->fp, &st);
if (st.st_size < (*block + 1) * CTREE_BLOCKSIZE) {
ret = ftruncate(root->fp,
(*block + 1) * CTREE_BLOCKSIZE);
if (ret) {
perror("ftruncate");
exit(1);
}
}
return ret;
} }
struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr) struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr)
@ -61,22 +41,23 @@ struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr)
return buf; return buf;
} }
struct tree_buffer *alloc_free_block(struct ctree_root *root) struct tree_buffer *find_tree_block(struct ctree_root *root, u64 blocknr)
{ {
u64 free_block; struct tree_buffer *buf;
int ret; buf = radix_tree_lookup(&root->cache_radix, blocknr);
struct tree_buffer * buf; if (buf) {
ret = get_free_block(root, &free_block); buf->count++;
if (ret) { } else {
BUG(); buf = alloc_tree_block(root, blocknr);
return NULL; if (!buf) {
BUG();
return NULL;
}
} }
buf = alloc_tree_block(root, free_block);
if (!buf)
BUG();
return buf; return buf;
} }
struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr) struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr)
{ {
loff_t offset = blocknr * CTREE_BLOCKSIZE; loff_t offset = blocknr * CTREE_BLOCKSIZE;
@ -86,20 +67,17 @@ struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr)
buf = radix_tree_lookup(&root->cache_radix, blocknr); buf = radix_tree_lookup(&root->cache_radix, blocknr);
if (buf) { if (buf) {
buf->count++; buf->count++;
goto test; } else {
buf = alloc_tree_block(root, blocknr);
if (!buf)
return NULL;
ret = pread(root->fp, &buf->node, CTREE_BLOCKSIZE, offset);
if (ret != CTREE_BLOCKSIZE) {
free(buf);
return NULL;
}
} }
buf = alloc_tree_block(root, blocknr); if (check_tree_block(root, buf))
if (!buf)
return NULL;
ret = pread(root->fp, &buf->node, CTREE_BLOCKSIZE, offset);
if (ret != CTREE_BLOCKSIZE) {
free(buf);
return NULL;
}
test:
if (buf->blocknr != buf->node.header.blocknr)
BUG();
if (root->node && buf->node.header.parentid != root->node->node.header.parentid)
BUG(); BUG();
return buf; return buf;
} }
@ -121,17 +99,10 @@ int write_tree_block(struct ctree_root *root, struct tree_buffer *buf)
static int __setup_root(struct ctree_root *root, struct ctree_root *extent_root, static int __setup_root(struct ctree_root *root, struct ctree_root *extent_root,
struct ctree_root_info *info, int fp) struct ctree_root_info *info, int fp)
{ {
INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
root->fp = fp; root->fp = fp;
root->node = NULL; root->node = NULL;
root->node = read_tree_block(root, info->tree_root); root->node = read_tree_block(root, info->tree_root);
root->extent_root = extent_root; root->extent_root = extent_root;
memcpy(&root->ai1, &info->alloc_extent, sizeof(info->alloc_extent));
memcpy(&root->ai2, &info->reserve_extent, sizeof(info->reserve_extent));
root->alloc_extent = &root->ai1;
root->reserve_extent = &root->ai2;
printf("setup done reading root %p, used %lu available %lu\n", root, root->alloc_extent->num_used, root->alloc_extent->num_blocks);
printf("setup done reading root %p, reserve used %lu available %lu\n", root, root->reserve_extent->num_used, root->reserve_extent->num_blocks);
return 0; return 0;
} }
@ -147,6 +118,8 @@ struct ctree_root *open_ctree(char *filename, struct ctree_super_block *super)
free(root); free(root);
return NULL; return NULL;
} }
INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
INIT_RADIX_TREE(&extent_root->cache_radix, GFP_KERNEL);
ret = pread(fp, super, sizeof(struct ctree_super_block), ret = pread(fp, super, sizeof(struct ctree_super_block),
CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE)); CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE));
if (ret == 0 || super->root_info.tree_root == 0) { if (ret == 0 || super->root_info.tree_root == 0) {
@ -168,8 +141,6 @@ struct ctree_root *open_ctree(char *filename, struct ctree_super_block *super)
static int __update_root(struct ctree_root *root, struct ctree_root_info *info) static int __update_root(struct ctree_root *root, struct ctree_root_info *info)
{ {
info->tree_root = root->node->blocknr; info->tree_root = root->node->blocknr;
memcpy(&info->alloc_extent, root->alloc_extent, sizeof(struct alloc_extent));
memcpy(&info->reserve_extent, root->reserve_extent, sizeof(struct alloc_extent));
return 0; return 0;
} }
@ -201,6 +172,7 @@ int close_ctree(struct ctree_root *root)
void tree_block_release(struct ctree_root *root, struct tree_buffer *buf) void tree_block_release(struct ctree_root *root, struct tree_buffer *buf)
{ {
buf->count--; buf->count--;
write_tree_block(root, buf);
if (buf->count < 0) if (buf->count < 0)
BUG(); BUG();
if (buf->count == 0) { if (buf->count == 0) {

2
fs/btrfs/disk-io.h
View file

@ -11,11 +11,11 @@ struct tree_buffer {
}; };
struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr); struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr);
struct tree_buffer *find_tree_block(struct ctree_root *root, u64 blocknr);
int write_tree_block(struct ctree_root *root, struct tree_buffer *buf); int write_tree_block(struct ctree_root *root, struct tree_buffer *buf);
struct ctree_root *open_ctree(char *filename, struct ctree_super_block *s); struct ctree_root *open_ctree(char *filename, struct ctree_super_block *s);
int close_ctree(struct ctree_root *root); int close_ctree(struct ctree_root *root);
void tree_block_release(struct ctree_root *root, struct tree_buffer *buf); void tree_block_release(struct ctree_root *root, struct tree_buffer *buf);
struct tree_buffer *alloc_free_block(struct ctree_root *root);
int write_ctree_super(struct ctree_root *root, struct ctree_super_block *s); int write_ctree_super(struct ctree_root *root, struct ctree_super_block *s);
int mkfs(int fd); int mkfs(int fd);

37
fs/btrfs/mkfs.c
View file

@ -23,17 +23,10 @@ int mkfs(int fd)
info[0].blocknr = 16; info[0].blocknr = 16;
info[0].objectid = 1; info[0].objectid = 1;
info[0].tree_root = 17; info[0].tree_root = 17;
info[0].alloc_extent.blocknr = 0;
info[0].alloc_extent.num_blocks = 64;
/* 0-17 are used (inclusive) */
info[0].alloc_extent.num_used = 18;
info[1].blocknr = 16; info[1].blocknr = 16;
info[1].objectid = 2; info[1].objectid = 2;
info[1].tree_root = 64; info[1].tree_root = 18;
info[1].alloc_extent.blocknr = 64;
info[1].alloc_extent.num_blocks = 64;
info[1].alloc_extent.num_used = 1;
ret = pwrite(fd, info, sizeof(info), ret = pwrite(fd, info, sizeof(info),
CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE)); CTREE_SUPER_INFO_OFFSET(CTREE_BLOCKSIZE));
if (ret != sizeof(info)) if (ret != sizeof(info))
@ -48,24 +41,36 @@ int mkfs(int fd)
return -1; return -1;
empty_leaf.header.parentid = 2; empty_leaf.header.parentid = 2;
empty_leaf.header.blocknr = 64; empty_leaf.header.blocknr = 18;
empty_leaf.header.nritems = 2; empty_leaf.header.nritems = 3;
/* item1, reserve blocks 0-16 */
item.key.objectid = 0; item.key.objectid = 0;
item.key.offset = 64; item.key.offset = 17;
item.key.flags = 0; item.key.flags = 0;
item.offset = LEAF_DATA_SIZE - sizeof(struct extent_item); item.offset = LEAF_DATA_SIZE - sizeof(struct extent_item);
item.size = sizeof(struct extent_item); item.size = sizeof(struct extent_item);
extent_item.refs = 1; extent_item.refs = 1;
extent_item.owner = 1; extent_item.owner = 0;
memcpy(empty_leaf.items, &item, sizeof(item)); memcpy(empty_leaf.items, &item, sizeof(item));
memcpy(empty_leaf.data + item.offset, &extent_item, item.size); memcpy(empty_leaf.data + item.offset, &extent_item, item.size);
item.key.objectid = 64;
item.key.offset = 64; /* item2, give block 17 to the root */
item.key.objectid = 17;
item.key.offset = 1;
item.offset = LEAF_DATA_SIZE - sizeof(struct extent_item) * 2; item.offset = LEAF_DATA_SIZE - sizeof(struct extent_item) * 2;
extent_item.owner = 2; extent_item.owner = 1;
memcpy(empty_leaf.items + 1, &item, sizeof(item)); memcpy(empty_leaf.items + 1, &item, sizeof(item));
memcpy(empty_leaf.data + item.offset, &extent_item, item.size); memcpy(empty_leaf.data + item.offset, &extent_item, item.size);
ret = pwrite(fd, &empty_leaf, sizeof(empty_leaf), 64 * CTREE_BLOCKSIZE);
/* item3, give block 18 for the extent root */
item.key.objectid = 18;
item.key.offset = 1;
item.offset = LEAF_DATA_SIZE - sizeof(struct extent_item) * 3;
extent_item.owner = 2;
memcpy(empty_leaf.items + 2, &item, sizeof(item));
memcpy(empty_leaf.data + item.offset, &extent_item, item.size);
ret = pwrite(fd, &empty_leaf, sizeof(empty_leaf), 18 * CTREE_BLOCKSIZE);
if (ret != sizeof(empty_leaf)) if (ret != sizeof(empty_leaf))
return -1; return -1;
return 0; return 0;